col(1)                                                     col(1)



     NAME
          col - filter text containing printer control  sequences  for
          use at a display device

     SYNOPSIS
          col [-b] [-f] [-p] [-x]

     DESCRIPTION
          col reads from the standard input and writes onto the stan-
          dard output.  It performs the line overlays implied by re-
          verse linefeeds (ASCII code ESCAPE-7), and by forward and
          reverse half-linefeeds (ESCAPE-9 and (ESCAPE-8). col is par-
          ticularly useful for filtering multicolumn output made with
          the .rt command of nroff and output resulting from use of
          the tbl(1) preprocessor.

          If the -b flag option is given, col assumes that the output
          device in use is not capable of backspacing.  In this case,
          if two or more characters are to appear in the same place,
          only the last one read will be output.

          Although col accepts half-line motions in its input, it nor-
          mally does not emit them on output.  Instead, text that
          would appear between lines is moved to the next lower full-
          line boundary.  This treatment can be suppressed by the -f
          (fine) flag option; in this case, the output from col may
          contain forward half-linefeeds (ESCAPE-9), but will still
          never contain either kind of reverse line motion.

          Unless the -x flag option is given, col will convert white
          space to tabs on output wherever possible to shorten print-
          ing time.

          The ASCII control characters SO (\016) and SI (\017) are as-
          sumed by col to start and end text in an alternate character
          set.  The character set to which each input character be-
          longs is remembered, and on output SI and SO characters are
          generated as appropriate to ensure that each character is
          printed in the correct character set.

          On input, the only control characters accepted are space,
          backspace, tab, return, SI , SO , T (\013), and escape fol-
          lowed by 7, 8, or 9.  The VT character is an alternate form
          of full reverse linefeed, included for compatibility with
          some earlier programs of this type.  All other nonprinting
          characters are ignored.

          Normally, col will ignore any unknown escape sequences found
          in its input; the -p flag option may be used to cause col to
          generate these sequences as regular characters, subject to
          overprinting from reverse line motions.  The use of this
          flag option is highly discouraged unless the user is fully



     April, 1990                                                     1

     col(1)                                                     col(1)



          aware of the textual position of the escape sequences.

     EXAMPLES
               nroff -mm filea | col

          pipes multicolumn nroff output through the col filter to en-
          able proper creation of columns.

     FILES
          /usr/bin/col

     SEE ALSO
          colcrt(1), nroff(1), tbl(1).

     NOTES
          The input format accepted by col matches the output produced
          by nroff with either the -T37 or -Tlp flag options.  Use
          -T37 (and the -f flag option of col) if the ultimate dispo-
          sition of the output of col will be a device that can inter-
          pret half-line motions, and -Tlp otherwise.

     BUGS
          Cannot back up more than 128 lines.
          Allows at most 800 characters, including backspaces, on a
          line.
          Local vertical motions that would result in backing up over
          the first line of the document are ignored.  As a result,
          the first line must not have any superscripts.



























     2                                                     April, 1990